What should you know about persistent headache after flu?

Dehydration, sinus pressure, poor sleep, fever, medication overuse and post-infectious symptoms can prolong head pain. A headache that is new, progressively worse, different from your usual pattern or worse in the morning needs attention. Brain tumours can present with headache, but headache alone does not show that a tumour is present. Brain metastases and glioblastoma may cause headache alongside other changes such as vomiting, seizures, vision problems, confusion or weakness.

Note where the pain is, how it began, what makes it worse, and whether fever or flu symptoms have resolved. Tell the clinician about recent medicines, head injury, cancer history and any change in balance, speech, sensation or strength.

Arrange medical review when the headache continues beyond the expected illness, keeps returning or interferes with sleep and activity. Rest, fluids and a regular sleep pattern may help while you arrange advice. Use pain medicine only as directed and avoid repeatedly adding different products without checking their ingredients. A clinician may perform a neurological examination and decide whether further tests are appropriate.

Seek emergency help for a sudden severe headache, new seizure, fainting, confusion, weakness or numbness on one side, difficulty speaking, loss of vision, repeated vomiting, stiff neck with fever or a headache after a significant head injury. If you have a known cancer diagnosis, report a new or worsening headache to your oncology team promptly.

Ask whether the headache pattern suggests infection, medication effects, migraine or another cause; whether examination or imaging is needed; and which changes should trigger urgent contact. Share a simple diary of timing, severity, medicines and associated symptoms.